Bit-brace jaw.



PATENTED JAN. 16, 1906.

R. G. ELLRICH.

BIT BRACE JAW.

APPLICATION FILED APR. 7, 1905.

Mil/2165365.-

UNITED STATES PATENT OFFICE.

ROBERT C. ELLRICH, OF SOUTI-IINGTON, CONNECTICUT, ASSIGNOR TO PECK, STOV @c WIILCOX COMPANY, OF SOUTHINGTON, CONNECTI- CUT, A CORPORATION OF CONNECTICUT.

Specification of Letters Patent.

Patented Jan. 16, 1906.

Application led April '7, 1905. Serial No. 254,406.

To all whom t may con/cern:

Be it known that I, ROBERT C. ELLRicI-l, a citizen of the United States of America, residing at Southington, in the county of I'Iartford and State of Connecticut, have invented certain new and useful Improvements in Bit-Brace Jaws, of which the following is a specification.

The object of the invention is to produce a device of the class specified having features of novelty and advantage.

In the drawings, Figure l is a sectional side elevation showing the aws `gripping a toolshank and the closing-sleeve in dotted lines. Fig. 2 is a sectional side elevation showing the jaws open. Fig. 3 is a view looking at the inner face of one of the jaws.

In the preferred embodiment of my invention illustrated in the drawings, a b are the jaws, preferably having their inner or opposing faces a b serrated transversely and grooved longitudinally to provide suitable gripping portions for the tool-shank. The outer ends of the jaws are beveled, as at a2 b2, so that when they are engaged by the jawclosing sleeve c they are forced toward each other onto the tool-shank to grip and hold it. It is customary to connect the inner ends of the jaws by a spring which will normally throw their outer ends away from each other, with the result that when the sleeve c is turned off ofthe jaws they move, under the` impulse of the spring, to the position shown in Fig. 2 to permit of the withdrawal of one tool and the insertion of another.

My invention relates particularly to the manner of connecting the jaws by the spring. The arms e e of the bowed spring d lie in the grooves in the inner faces of the jaws, their ends e e being bent out through apertures f j in the jaws, which are formed intermediate of their length, but preferably nearer to the outer than the inner ends of the aws. The

inner ends of the jaws are transversely slotted to form recesses to receive the bow of the spring to permit said spring to play freely through said slots and allow the inner ends of the jaws to be brought closely together. Preferably the ends of the springs which pass through the apertures in the jaws are bent over or in some other way secured thereto.

In operation it will be seen that while normally the spring tends to draw the inner ends of the jaws together and throw the outer ends apart, forming a substantially V-opening between the jaws, when the jaws are closed onto a tool-shank, and especially a shank of large diameter, the inner ends of the jaws are free to separate and that when the jaws are In all other bit-jaws with which I am fa-V miliar the spring passes around or through the inner ends ol' the jaws, and consequently binds them together, preventing their open- Y `mg to any considerable extent.

In consequence when a tool having a shank of large diameter is to be held by the jaws the contact of the jaws on the shank is extremely small as compared with the construction herein illustrated and described.

g represents the shank of a tool as it appears inplace in the jaws.

I claim as my invention- A bit-brace jaw comprising the two independent jaw members having their opposing surfaces longitudinally grooved and their rear ends transversely slotted, and a bowed spring, shaped to afford its spring action in the bow or curve, located wholly between said jaws with arms in said grooves, and the bow adapted to play through the slots in the rear ends of said jaws as said rear ends approach each other.

In testimony whereof I afiix my signature in presence of two witnesses.

ROBERT C. ELLRICH.

lVitnesses:

THOMAS F. WELCH, MARCUS II. IIOLCOMB. 

